Detection and quantification of antigens, analytes or other microparticulates is important in diagnosing and treating many conditions that impair human health. For example, identifying CD4 T-cell counts in patients provide physicians with information of the patient's HIV infection status. Healthcare providers often take multiple CD4 T-cell counts over time in order to determine the progression of the disease and the effectiveness of HIV treatments. A falling CD4 T-cell count indicates that HIV is progressing and damaging the immune system, whereas a rising CD4 T-cell count indicates that HIV treatments are altering the course of the disease.